Polypropylene support for photographic use

ABSTRACT

The present invention is directed to the use of polypropylene supports for photographic materials. The support contains 15 to 35% by weight of talc, 3 to 15% by weight of titanium white and 0.1 to 5% by weight of a fatty acid metal salt.

United States Patent 1191 Komatsu et al.

[ June 10, 1975 POLYPROPYLENE SUPPORT FOR PHOTOGRAPHIC USE Inventors: Hajime Komatsu, Odawara; Seio Mukai, lchihara, both of Japan Assignees: Konishiroku Photo Industry Co.,

Ltd., Tokyo; Chisso Corporation, Osaka, both of Japan Filed: Jan. 28, 1974 Appl. No.; 437,244

Foreign Application Priority Data Jan. 29, 1973 Japan 48-11156 Jan. 29, 1973 Japan 48-,11157 US. Cl..... 96/87 R; 117/1388 E; 117/161 UB;

260/23 H; 260/42.46 Int. Cl G03c l/78; B44d l/22 Field of Search 96/87 R, 87 A, 3, 100,

96/74 260/23 H, 42.46; 117/1388 E, 161 UB Primary ExaminerNorman G. Torchin Assistant Examiner.l. P. Brammer Attorney, Agent, or FirmWaters, Schwartz & Nissen [5 7] ABSTRACT The present invention is directed to the use of polypropylene supports for photographic materials. The support contains 15 to 35% by weight of talc, 3 to 15% by weight of titanium white and 0.1 to 5% by weight of a fatty acid metal salt.

9 Claims, No Drawings 1 POLYPROPYLENE SUPPORT FOR PHOTOGRAPHIC USE This invention relates to a support for use in a lightsensitive photographic material. More particularly, the present invention is concerned with a support for lightsensitive silver halide photographic printing material which is composed of a polypropylene sheet.

A baryta paper, which has generally been used as a support for light-sensitive silver halide photographic printing material, is undesirably high in water absorption despite of its being excellent in whiteness, opacity, rigidity, etc. Accordingly, a silver halide photographic material using the baryta paper as support has such disadvantages that when subjected to photographic treatment, the photographic material not only consumes large quantities of developing, fixing, bleaching and the like processing solutions and hence is required to be subjected to water-washing over a long period of time, but also gives a print which is inferior in gloss and smoothness of its surface so that the print cannot be made sufficient in gloss and smoothness unless there is adopted such specific finishing step as ferrotype drying.

In order to overcome the above-mentioned disadvantages, there has been made such attempt that in place of the baryta paper, a so-called polyethylene laminate paper prepared by applying onto both sides of a paper a thin film composed mainly of a polyethylene, for example, is used as the support for silver halide photographic material. However, the polyethylene laminate paper is low in rigidity and hence has such disadvantage that it should be made great in thickness so as to be made high in rigidity required for a printing material. Since the polyethylene laminate paper is lower in water absorption than the baryta paper, the amounts of processing solutions consumed in the photographic treatment of a photographic material using the polyethylene laminate paper as support are smaller and the period of time required for water-washing of the photographic material may be made shorter. During the photographic treatment, however, the processing solutions penetrate into the paper, which is the intermediary substrate of the laminate, through its cross-section. Accordingly, when the said photographic material is subjected to rapid processing, wherein the water-washing treatment is conducted only for a short period of time, there is brought about such disadvantage that stains are formed at the peripheral portion of the print due to residual processing solutions which have penetrated into the intermediary paper substrate through its crosssection. Even when there is not adopted such finishing step as ferrotype drying, the photographic material using the polyethylene laminate paper can give a print which is higher in gloss and smoothness than in the case where the baryta paper is used. However, the surface of the polyethylene layer is not sufficient in smoothness due to the arrangement of pulp fibers of the paper, and thus it is still impossible to say that the resulting print is sufficient in gloss. Further, the polyethylene laminate paper, due to its laminate structure, has such disadvantage that the procedure for preparation of the laminate paper itself is quite uneconomical due to the increased number of steps.

The object of the present invention is to provide a support for lightsensitive photographic printing material which is free from the above-mentioned disadvantages.

Another object of the invention is to provide a lightsensitive silver halide photographic printing material having a silver halide emulsion layer which has been firmly adhered to the above-mentioned support.

The said object can be accomplished by using as the support a polypropylene sheet comprising a main resin component of a polypropylene having a melt flow index (hereinafter abbreviated to MFI) of 5 to 100, 15 to 35% by weight of talc, 3 to 15% by weight of titanium white, and 0.1 to 5% by weight of a fatty acid metal salt.

The another object can be accomplished as mentioned below. In the case where a silver halide emulsion layer is formed on the said support, a compound having at least two ethyleneimino groups in one molecule and, in combination therewith, at least one water-dispersible particulate high molecular substance composed of a homopolymer of ethyl acrylate or butyl acrylate, or a copolymer of at least one of ethyl acrylate and butyl acrylate with vinylidene chloride into a gelatin-containin g layer which is in contact with said support, i.e. into a gelatin-containing sub layer, when such sub layer is used, or into the silver halide emulsion layer to be directly adhered to the support, when no such sub layer is used. It is well known that a polypropylene sheet is made white and opaque by incorporation of a white pigment such as titanium white or the like, in general. By mere incorporation of such white pigment, however, the polypropylene sheet cannot be made higher in rigidity. In case the polypropylene sheet is desired to be enhanced also in rigidity, therefore, fine powdery talc should additionally be incorporated therein. However, when a polypropylene sheet incorporated with said titanium white and talc is used as the support of a light-sensitive photographic printing material, fog derived from the tale is undesirably formed in the silver halide emulsion layer to deteriorate the photographic properties of the resulting print. Furthermore, by incorporation of the tale, not only the support is decreased in whiteness but also the resulting print becomes extremely low in gloss.

We have found that a polypropylene sheet incorporated with titanium white and talc is additionally incorporated with a fatty acid metal salt, whereby the polypropylene sheet, when used as the support of a lightsensitive photographic material, can be made free from such disadvantages derived from talc as mentioned above.

The polypropylene used as the main resin component of the polypropylene sheet according to the present invention is a homopolymer of propylene or a copolymer comprising a major proportion of propylene and a minor proportion of ethylene or other a-olefin, and has an MFI of 5 to 100. In case a polypropylene having an MFI of less than 5 is used, it is rather difficult to obtain a print which is sufficient in gloss. This tendency is particularly marked when the amount of talc incorporated is large. In case a polypropylene having an MFI of more than is used, the resulting sheet is undesirably embrittled to a great extent.

As the polypropylene, the homopolymer of propylene is most preferred. The propylene homopolymer as compared with a propylene copolymer has a greater rigidity and this serves to prevent curling caused by the dimensional change of a photographic emulsion layer due to temperature variation. Further, the homopolymer has a higher heat deformation temperature than the copolymer, and because of this, use of the homopolymer enables to employ high temperature drying with avoiding the possible deformation of selvedge portions of film strips during any drying step for photographic preparation and handling. This means considerable economical advantages such as time saving and simplified drying apparatus.

In addition, the propylene homopolymer which has a higher solidification temperature than the propylene copolymer allows to shorten a cooling time required for shaping and consequently makes the shaping of poly propylene support more speedy. The homopolymer is free from any undesired high molecular weight polymeric mass which is sometimes observed in the block copolymer of propylene as the result of homopolymerization of its comonomer, and so it can make sure more uniform dispersion of talc, pigment, etc., therein.

In the polypropylene sheet according to the present invention, any other suitable resin component may be used, if necessary, in such a small amount as not to injure the effect of the present invention. Suitable as such additional resin component are included polyethylenes, the randam copolymers of polypropylene with ethylene or other a-olefins, polyisobutylenes, etc. Incorporation of 3 to 20% of an ethylene-propylene rubber or a polyisobutylene into the propylene homopolymer is particularly advantageous because it improves brittleness of said homopolymer without sacrifying desirable rigidity, high heat deformation temperature, high solidification temperature, etc., which are inherent to the propylene homopolymer.

Talc is markedly effective for enhancing the rigidity of a polypropylene sheet and is also useful for increasing the opacity thereof, but sometimes decreases the whiteness and gloss. In the present invention, therefore, it is desirable to use fine powdery talc having an average particle size of less than microns, preferably less than 5 microns. The amount of the said talc to be added is to 35% by weight based on the weight of the polypropylene sheet. In case the amount of the tale is less than 15% by weight, the polypropylene sheet is insufficient in rigidity, while in case the amount thereof is more than 35% by weight, the sheet becomes too brittle to be put into practical use.

Among white pigments, titanium white is particularly excellent in hiding power and hence is preferably used in the present invention. The amount of titanium white to be added is 3 to 15% by weight based on the weight of the polypropylene sheet. When titanium white is added in such amount as mentioned above, the sheet becomes sufficient in opacity and whiteness. In case the amount of titanium white is less than 3% by weight, the sheet is insufficient in opacity, while the addition of titanium white in such an amount as more than 15% by weight is not only uneconomical but also becomes a cause for embrittlement of the sheet. The average particle size of titanium white is ordinarily less than 1 micron. When such titanium white is used, the sheet is not decreased in gloss. Generally, titanium white is classified into rutileand anatase-type crystal structures. In the present invention, titanium white of any crystal structure may be used. Particularly when a polypropylene sheet higher in opacity is desired to be obtained, however, titanium white of the anatase type structure is preferably used, since it shows a brighter whiteness.

The fatty acid metal salt used in the present invention not only inhibits the formation of fog derived from talc as mentioned previously, but also serves to enhance the polypropylene sheet in whiteness and gloss. The amount of the fatty acid metal salt to be added is preferably 0.1 to 5% by weight based on the weight of the polypropylene sheet. In case the amount of the fatty acid metal salt is less than 0.1% by weight, the formation of fog cannot sufficiently be inhibited, while in case the amount thereof is more than 5% by weight, the metal salt exduates out on the surface of the polypropylene sheet, and, due to its releasing effect, the sheet is deteriorated in adhesion to silver halide emulsion layer or sub layer and tends to cause peeling of film. As the fatty acid metal salt, there may effectively be used a metal salt of a saturated or unsaturated fatty acid having 8 to 22 carbon atoms which can be easily obtained commercially. Typical examples of such metal salt are salts of lithium, magnesium, calcium, zinc, aluminum and the like metals of stearic, palmitic and oleic acids.

The polypropylene sheet according to the present invention may be incorporated with, in addition to such talc, titanium white and fatty acid metal salt as mentioned previously, any of such other additives as, for example, stabilizers, particularly phenolic stabilizers, antistatic agents, auxiliary fillers and pigments, brighteners, plasticizers, etc., in such proper amounts as not to injure the effect of the present invention.

For preparation of the polypropylene sheet of the present invention, a conventional process for preparing a polypropylene sheet may be utilized as it is. Preferably, however, it is desirable to adopt such a process that a resin composition comprising the aforesaid components which has been melted and kneaded by use of an extruder is extruded through a T-die and then subjected to a chill-roll, so that one side of the resulting sheet comes to have a mirror surface, or if necessary a rough surface having a controlled roughness, e.g. a reticular surface such as silk surface, and the other side of the sheet comes to have a surface which has been so roughened as to be writable.

A silver halide emulsion is coated on the polypropylene sheet prepared according to the abovementioned process and is then dried, whereby a light-sensitive silver halide photographic material can be obtained. The coating of the silver halide emulsion on the polypropyl ene sheet may be carried out in the same manner as in the case of a polyethylene laminate paper. That is, the surface of the polypropylene sheet is previously subjected to corona discharge treatment, flame treatment or oxidize treatment to enhance the adhesion thereof to silver halide emulsion layer, and then the silver halide emulsion is directly coated on the sheet surface. If necessary, the polypropylene sheet is subjected to subbing treatment to form a sub layer thereon, and then the silver halide emulsion is coated on the sub layer. In the above manner, a light-ser.sitive silver halide photographic printing material free from peeling of coating can be obtained.

In case a photographic material consisting of a silver halide emulsion layer and a support is desired to be subjected to such severe photographic treatment as high temperature quick development using an automatic developing machine, the silver halide emulsion layer should have been adhered particularly firmly to the support. We have found a procedure for firmly adhering a silver halide emulsion to such a support as the aforesaid polypropylene sheet. That'is, we have found that in forming a silver halide emulsion layer on the polypropylene sheet of the present invention, a compound having at least two ethyleneimino groups in one Continued molecule and, in combination therewith, at least one water-dispersible particulate high molecular substance (11') El 3 composed of a homopolymer of ethyl acrylate or butyl acrylate, or a copolymer of at least one of ethyl acrylate 5 and butyl acrylate with vinylidene chloride, are incor- The above-mentioned compound is known as a hardener for such colloid as gelatin, caseine or gum carabic, and is sometimes incorporated into a silver halide emulsion. When the said compound is used singly, the silver halide emulsion layer is not so enhanced in adhesion to the support, i.e. the polypropylene sheet of the present invention. However, when the compound is used in combination with such water-dispersible particulate high molecular substance as mentioned previously, the silver halide emulsion layer is greatly enhanced in adhesion to the support.

The water-dispersible particulate high molecular substance used in the present invention is a plastic substance having an average particle size of less than about 0.5 micron which is composed of a homopolymer of ethyl acrylate or butyl acrylate, or a copolymer of at least one of ethyl acrylate and butyl acrylate with vinylidene chloride. The said high molecular substance can easily be prepared according to emulsion polymerization using such anion activator as sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, sodium aryl polyethylene glycol ether sulfonate or sodium alkyl polyethylene glycol ether sulfonate as emulsifier, and alkali persulfate, ammonium persulfate or hydrogen peroxide as polymerization initiator. The molecular weight of the high molecular substance is preferably about 10,000 to 1,000,000. In case of the high molecular substance composed of a copolymer of such acrylate as ethylacrylate or butyl acrylate with vinylidene chloride, the ratio of acrylate to vinylidene chloride is preferably from :90 to 90:10.

Concrete procedures for synthesizing the said high molecular substance are explained below with reference to a synthesis example.

Synthesis Example (Synthesis of a water-dispersible particulate high molecular substance composed of a nbutyl acrylate-vinylidene chloride copolymer):

Into a 1 liter, four-necked flask equipped with a stirrer, a thermometer, a dropping funnel, a nitrogen inlet tube and a reflux condenser, 500 ml. of water was charged and nitrogen gas was introduced for 30minutes. Subsequently, 10.5 g. of sodium dodecyl sulfate was added to the flask. The temperature of the flask was elevated to 30C., and'then 3.92 g. of ammonium persulfate and 1.86 g. of acid sodium sulfite were added to the flask. Immediately thereafter, a mixed liquid comprising 65.3 g. of n-butyl acrylate and 65.3 g. of vinylidene chloride was dropped into the flask over a period of one hour. After completion of the dropping, the content of the flask was allowed to react at 45C. for 4 hours, and the reaction product was recovered by filtration to obtain a water-dispersible particulate high molecular substance with a conversion of 96.7%. The thus obtained substance had an activator content of 1.7%, a specific gravity (di of 1.051 and an average particle size of 0.1 micron, and a 1% dispersion of said substance had a transmission of 73.2%.

In the present invention, at least one of such substance as synthesized in the above-mentioned manner is incorporated, either as it is or in the form of an aqueous dispersion, into a gelatin-containing subbing solution or into a silver halide emulsion when the emulsion is to be directly coated on the support, i.e. the polypropylene sheet of the present invention. The said substance may be incorporated at any stage during preparation of the subbing solution or the silver halide emulsion, and the amount thereof is preferably about 5 to 60% by weight based on the weight of the gelatin in said solution or emulsion.

In case the water-dispersible particulate high molecular substance according to the present invention is used singly, the silver halide emulsion layer is not so enhanced in adhesion to the polypropylene sheet of the present invention. However, when the said substance is used in 37 combination with the aforesaid compound having at least two ethyleneimino groups in one molecule, the silver halide emulsion layer is greatly enhanced in adhesion to the polypropylene sheet.

In addition to the high molecular substance used in the present invention, there are such water-dispersible particulate high molecular substances as, for example, polyvinyl acetate, polyvinylidene chloride, styrenebutadiene copolymer, vinyl acetate-ethylene copolymer, acrylonitrile-butadiene copolymer and vinyl acetate-acrylate copolymer. Even when any of these substances is used singly or in combination with the compound having at least two ethyleneimino groups in one molecule, the silver halide emulsion layer is not enhanced in adhesion to the polypropylene sheet. Likewise, even when any of such substances other than the compound having at least two ethyleneimino groups in one molecule as, for example, aldehydes, ,B-diketones and epoxy compounds, which are known as hardeners for gelatin and the like, is used in combination with the water-dispersible particulate high molecular substance according to the present invention, no such adhesionenhancing effect as in the present invention is observed. Thus, the effect of the present invention cannot be attained unless a specific hardener is used in combination with a specific water-dispersible particulate high molecular substance. Moreover, the adhesion according to the present invention is so great that a sufficient adhesion strength can advantageously be obtained in some cases even if the polypropylene sheet is not subjected to such hydrophilization treatment, as corona discharge treatment.

The amount of the compound having at least two ethyleneimino groups in one molecule which is used in the present invention varies depending on the kind of the layer into which the compound is to be incorporated, the kind of the silver halide emulsion used, and the kind and amount of the water-dispersible particulate high molecular substance used in combination with said compound. Generally, a sufficient effect can be obtained when the amount of said compound is 0.1 to 10% by weight based on the amount of gelatin in the layer, into which the compound is to be incorporated. However, the said compound is, of course, not limited to be used in such amount as mentioned above, but may be used in an optional amount so far as the effect of the present invention can be obtained. The compound may be added at any stage during preparation of the subbing solution or silver halide emulsion used to form a sub layer or silver halide emulsion layer, but is preferably added immediately before coating of the solution or emulsion.

The silver halide emulsion applicable to the support of the present invention may contain any of such silver halides as silver bromide, silver chloride and silver iodide, and mixtures thereof such assilver chlorobromide, silver iodobromide, etc., and may be any of the high and low speed type emulsions. The silver halide emulsion may be subjected to chemical sensitization such as sulfur-, reductionor gold-sensitization, or to optical sensitization using a sensitizing dye, and may be incorporated with any of various photographic additives such as stabilizers, antifoggants, ultraviolet absorbers, coating aids, etc. Further, the silver halide emulsion may be incorporated with couplers for forming a colored image by color development. In the present invention, not only one layer of the silver halide emulsion is formed on the support, but also two or more layers of silver halide emulsions different in composition may successively be formed thereon. 1f necessary, protective layer, filter layer, inter layer, antihalation layer, etc. may also be formed in addition to the said silver halide emulsion layers. The light-sensitive silver halide photographic material using as.the support the polypropylene sheet according to thepresent invention is particularly useful for contact printing or enlargement printing. When a high speed silver halide emulsion is used, however, the photographic material may be used for direct photographing by use of a special camera.

In accordance with the present invention, there is provided a support for light-sensitive silver halide photographic material which is markedly excellent in whiteness, opacity, rigidity, gloss, smoothness and nonwater absorption. At the time of development, a lightsensitive silver halide photographic material using the support according to the present invention consumes smaller amounts of developing, fixing bleaching and the like processing solutions and is extremely shorter in period of time required for water-washing treatment. Moreover, the photographic material can give a print markedly excellent in gloss and smoothness.

The present invention is illustrated in detail below with reference to examples, but the examples do not limit the scope of the invention.

The values of MP1, yellowness index (hereinafter abbreviated to YI) and fog density in the examples were measured according to the following methods:

MFI: ASTM D-1238 (230C., 2.16 kg.)

Y1: ASTM D-1925-63T (The smaller the Y1 value, the lower the yellowness and the higher the whiteness.)

Fog density: JIS K-7611-60 EXAMPLE 1 A mixture comprising 68.9% by weight of a powdery polypropylene having an MP1 of 7.0, 0.1% by weight of 2,6-di-tert-butyl p-cresol (hereinafter abbreviated to BHT) as an antioxidant, 15.0% by weight of fine powdery talc having an average particle size of 2.0 microns, 15.0% by weight of rutile type titanium white having an average particle size of 0.3 micron, and 1.0% by weight of any of such fatty acid metal salts as shown in Table 1 was sufficiently kneaded by means of a Henschel mixer, extruded by use of an extruder at 200C., and then cut to the form of grains. Using an ordinary sheet-making machine of T-die type, the grains were shaped at a melt temperature of 250C. to prepare a sheet having a thickness of 250 microns. In the above manner, sheet Nos. 1 to 10 were prepared by varying the kind of the fatty acid metal salt. The surface of each sheet was subjected to corona discharge treatment so that the contact angle of water became 60. Subsequently, an ordinary silver chlorobromoiodide emulsion for printing paper was coated on the treated surface of each sheet and then dried to obtain printing papers Nos. 1a to 10a.

Separately, a sheet No. 11 was prepared in the same manner as above, except that the fatty acid metal salt was not used and the powdery polypropylene wasused in an amount of 69.9% by weight, and then treated in the same manner as above to obtain a printing paper No. 1121. i

For comparison, commercially available baryta paper (sheet No. 12) and polyethylene laminate paper (sheet No. 13) were used as supports. The surface of the sheet No. 13 was subjected to corona discharge treatment. Thereafter, the same emulsion as mentioned above was coated on each of the sheet Nos. 12 and 13 and then dried to obtain printing paper Nos. 12a and 13a.

The YI values of the sheets and the fog density values of the printing papers were as shown in Table 1.

paper) From Table 1, it is understood that the sheet No. l 1, which was not incorporated with any fatty acid metal salt, is high in Y1 value, i.e. is low in whiteness and is yellowish, and hence cannot be put into practical use, whereas the sheet Nos. 1 to according to the present invention, which were incorporated with the fatty acid metal salts, are low in Y1 value and thus have greatly been enhanced in whiteness by incorporation of the fatty acid metal salts. It is also understood that such enhancement in whiteness is particularly marked when fatty acid salts of lithium, magnesium, aluminum and zinc are incorporated, and that the sheets incorporated with said fatty acid metal salts are more excellent in whiteness than the baryta paper (sheet No. 12) and the polyethylene laminate paper (sheet No. 13). Further, it is understood that the printing paper No. lla using as the support the sheet No. l l which was not incorporated with fatty acid metal salt, is extremely high in fog density, whereas the printing paper Nos. la to 10a using as the supports the sheet Nos. 1 to 10, which were incorporated with the fatty acid metal salts, are low in fog density and thus are marked in fog-inhibiting effect due to incorporation of the fatty acid metal salts into the sheets used as the supports.

The printing papers Nos. la to 10a according to the present invention were subjected to ordinary exposure and development, and then dried in hot air without the use of ferrotype to obtain prints which were markedly excellent in gloss.

EXAMPLE 2 A powdery polypropylene having an MP1 of 7.0, BHT as an antioxidant, fine talc powder having an average particle size of 1.5 microns, anatase-type titanium white having an average particle size of 0.3 micron, and zincstearate were blended together in such proportions (%by weight) as shown in Table 2 to form compositions of the prescriptions 1 to 4. The compositions were individually shaped in the same manner as in Example 1 to prepare sheet Nos. 14 to 17. After subjecting the surface of each sheet to corona discharge treatment, the same silver halide emulsion for printing as in Example l was coated on the treated surfaces of the sheets and then dried to obtain printing paper Nos. 14a to 17a.

The YI values of the sheets and the fog density values of the printing papers were as shown in Table 3.

T bl 3 Continued Prescription Sheet Yl Printing paper Fog densit No. No. y

From Table 3, it is understood that the sheet No. 17, which was not incorporated with fatty acid metal salt, is high in Y1 value, and the printing paper No. 17a using the sheet No. 17 as the support is high in fog density and hence cannot be put into practical use, whereas the sheet Nos. 14 to 16 according to the present invention have been enhanced in whiteness, and the printing papers Nos. to using the said sheets as theh supports are free from formation of fog.

The printing paper Nos. 14a to 16a according to the present invention were subject to ordinary exposure and development, and then dried in hot air without the use of ferrotype to obtain prints which were markedly excellent in gloss.

EXAMPLE 3 Each of polybutyl acrylate and a 1:1 styrenebutadiene copolymer as water-dispersible particulate high molecular substances, and each of the previously exemplified compound (1) and mucochloric acid as hardeners, were mixed together in such proportions as shown in Table 4, and the resulting mixture was added to 1 kg. of a silver chlorobromoiodide emulsion. The emulsion was coated on the polypropylene sheet No. 3 obtained in Example 1, after subjecting the sheet to corona discharge treatment, and then dried to prepare a sample. In the above manner, samples Nos. 1 to 19 were prepared by varying the kind and proportion of the waterdispersible high molecular substance and those of the hardener.

The samples were individually incubated at 50C. and 80 RH for 24 hours and at 25C. and 60% RH for 1 week, and then subjected to development. During the development and after drying, the samples were measured in adhesion of the emulsion layer to the polypropylene sheet to obtain such results as shown in Table 4.

Methods for measurement of the adhesion and standards for evaluation thereof were as shown below (the same methods and standards were adopted also in the examples shown later).

Method for measurement of adhesion:

During development:

The film of each sample during the development was scribed with a knife so as to form a checkered pattern, and then strongly rubbed with hand to observe whether the coating was peeled or not.

After drying:

The film of each sample after drying was scribed with a knife so as to form a checkered pattern, and an adhesive tape was firmly adhered to the film and then rapidly stripped to observe whether the film was peeled or not.

Standards for evaluation of adhesion:

A: The pattern was not peeled at all B: The corner of the pattern was slightly peeled.

C: A part of the pattern was peeled.

D: The whole pattern was peeled.

Table 4 Sample Particulate high incubated at lncubated at No. molecular substance Hardener 50C. 80%RH 25C. 60%RH (wt71 (ml) During After During After developdrying developdrying ment ment 1 C C C D 2 Polybutyl acrylate 5 Compound l) 50 A A A A 3 l 50 A A A A 4 2O 50 A A A A 5 40 50 A A A A 6 50 B C C C 7 Polybutyl acrylate 5 C C C C 8 l0 C C C C 9 2O B C C C 10 40 B C B C l I Styrene-butadicne copolymer 5 Compound (I) 50 C C C D l2 Styrene-butadiene Compound l 50 C C C C copolymer l0 l3 50 C C C C 14 40 50 C C C C l5 Mucochloric 50 C C C D acid l6 Polybutyl acrylate 5 50 C C C C l7 l0 50 C C C C l8 20 50 C C C C 19 4O 50 B C B C EXAMPLE 4 Each of the butyl acrylate-vinylidene chloride copolymer synthesized in the aforesaid Synthesis Example and a 1:1 butyl acrylate-vinyl acetate copolymer as water-dispersible high molecular substances, and each of the previously exemplified compound (2) and di- (chloromethylcarbonyl)-amine (DCA) as hardeners, were mixed together in such proportions as shown in Table 5, and the resulting mixture was added to 1 kg.

of a silver chlorobromoiodide emulsion containing oilsoluble couplers. The emulsion was coated on the polypropylene sheet No. 9 obtained in Example 1, after subjecting sheet to corona discharge treatment, and then dried to obtain a sample. In the above manner,

samples Nos. 20 to 29 were prepared by varying the kind and proportion of the water-dispersible high molecular substance and those of the hardener.

The samples were individually incubated under the same conditions as in Example 3, and then subjected to development. During the development and after drying, the samples were measured in adhesion of the emulsion layer to the polypropylene sheet in the same manner as in Example 3 to obtain such results as shown in Table 5.

Table 5 Sample Particulate high Hardener incubated at incubated at molecular substance C., 80/1RH 25C., %RH No. (wt7r) (ml) During After During After developdrying developdrying ment ment 20 C C C D Butyl acrylate- 2l vinylidene chloride 10 Compound (2) 50 A A A A copolymer 22 3O 50 A A A A 23 l0 C C C C 24 30 B C B C 25 l0 DCA 50 C C C C 26 30 50 B B C C 27 DCA 50 C C C D 28 Butyl acrylatevinyl acetate 30 C C C C copolymer 29 30 Compound (2) 50 C C C C 3 ,88 8 ,679 15 16 In Table 5, the amount of the particulate high molecbein based on the weight of said polypropylene supular substance is represented by weight based on the t.

weight of gelatin in the emulsion, and the amount of the A polypropylene Support as claimed in claim 1 hardener is represented by ml. of a 2% aqueous soluwherein Said polypropylene is the homopolymer of tion of the hardener. 5 propylene From Table It is "l that only.the i k 3. A polypropylene support as claimed in claim 1, 21 and 22 accordmg to the present mvemlon m having its surface treated with corona discharge or which the particulate butyl acrylatevmyhdene chloride flame copolymer was used in combination with the compound (2), are high in adhesion of the emulsion layer P lyp py e pport as claimed in claim 1 to the polypropylene Sheet. 7 wherein said support is subbed with a subbing composition comprising a hardener compound having at least EXAMPLE 5 two ethyleneimino groups in its molecule and a waterdispersible, particulate high molecular substance which is the homopolymer of ethyl acrylate or butyl acrylate. 5. A polypropylene support as claimed in claim 1, where said support is subbed with a subbing composition comprising a hardener compound having at least two ethyleneimino groups in its molecule and a waterdispersible, particulate high molecular substance which is the copolymer of ethyl acrylate or butyl acrylate with Polyethyl acrylate as a water-dispersible high molecular substance and the previously exemplified compound (18) as a hardener were mixed together in such proportions as shown in Table 6, and the resulting mixture was added to 1 kg. of a subbing solution comprising a 4% aqueous gelatin solution. Subsequently, the subbing solution was coated on the polypropylene 2O sheet No. 15 obtained in Example 2 and dried to form a sub layer, and then a silver chlorobromide emulsion vinylidene Chloride. was coated on the sub layer and dried to obtain 21 Sam- 6. A polypropylene support as claimed in claim 1 ple. In the above manner, samples Nos. 30 to 34 ere which bears thereon a light-sensitive silver halide pho- P p y Varying the Proportions of the h mol 25 tographic emulsion to form a light-sensitive photoular substance and the hardener. graphic material.

The Samples were incubated under the 7. A light..sensitive ilver photographic matesame conditions as in Exampl and then Subjected to rial which comprises at least one silver halide emulsion development. During the development and after drylayer d, as a support, a polypropylene Sheet i ing, the samples were measured in adhesion of the i a m i r si component ofapolypropylene h i emulsion layer to the polypropylene sheet in the same a melt flow index of 5 to 100, 15 to by weight of manner as in Example 3 to obtain such results as shown talc, 3 to 15% by weight of titanium white, and 0.1 to

in Table 6. 5% by weight of a fatty acid metal salt, characterized Table 6 Sample Particulate Compound (18) incubated at incubated at polyethyl 50C., 80% RH 25C., 60% RH No. acrylate (ml) During After During After (wt7() developdrying developdrying ment ment 30 c C c C 31 20 50 A A A A 32 A A A A 33 50 B C C C 34 20 C C C C 35 4O B C B C In Table 6, the amount of the particulate polyethyl in that the gelatin-containing layer which is in contact acrylate is represented by weight based on the weight with said support has been incorporated with a combiof gelatin in the subbing solution, and the amount of 50 nation of a compound having at least two the p u is represented y Of a 2% q ethyleneimino groups in one molecule with at least one Ous solution of the Compoundwater-dispersible particulate high molecular substance From Table 6, it is understood that even in the case composed f a homopolymer f th l acrylate or butyl where the water-dispersible particulate high molecular acrylate or a copolymer f at least one f h l acrylate substance and hardener according to the present invenand but] acrylate tion are added in combination to a gelatin subbing solu- A golypropylene Support as claimed in claim 3 i i z g i f layer 15 hlgh m adheslon to the poly which bears thereon a light-sensitive silver halide phop opy e e tographic emulsion to form a light-sensitive photo- What we claim is:

l. A polypropylene support for photographic use, comprising a main resin component of a polypropylene, together with 15 to 35% by weight of talc, 3 to 15% by weight of titanium white, and 0.1 to 5% by weight of a fatty acid metal salt, all the weight percents graphic material.

9. A polypropylene support as claimed in claim 4 which bears thereon a light-sensitive silver halide photographic emulsion to form a light-sensitive photographic material. 

1. A POLYPROPYLENE SUPPORT FOR PHOTOGRAPHIC USE, COMPRISING A MAIN RESIN COMPONENT OF A POLYPROPYLENE, TOGETHER WITH 15 TO 35% BY WEIGHT OF TALC, 3 TO 15% BY WEIGHT OF TITANIUM WHITE, AND 0.1 TO 5% BY WEIGHT OF A FATTY ACID METAL SALT, ALL THE WEIGHT PERCENTS BEING BASED ON THE WEIGHT OF SAID POLYPROPULENE SUPPORT.
 2. A polypropylene support as claimed in claim 1, wherein said polypropylene is the homopolymer of propylene.
 3. A polypropylene support as claimed in claim 1, having its surface treated with corona discharge or flame.
 4. A polypropylene support as claimed in claim 1, wherein said support is subbed with a subbing composition comprising a hardener compound having at least two ethyleneimino groups in its molecule and a water-dispersible, particulate high molecular substance which is the homopolymer of ethyl acrylate or butyl acrylate.
 5. A polypropylene support as claimed in claim 1, where said support is subbed with a subbing composition comprising a hardener compound having at least two ethyleneimino groups in its molecule and a water-dispersible, particulate high molecular substance which is the copolymer of ethyl acrylate or butyl acrylate with vinylidene chloride.
 6. A polypropylene support as claimed in claim 1 which bears thereon a light-sensitive silver halide photographic emulsion to form a light-sensitive photographic material.
 7. A light-sensitive silver halide photographic material which comprises at least one silver halide emulsion layer and, as a support, a polypropylene sheet comprising a main resin component of a polypropylene having a melt flow index of 5 to 100, 15 to 35% by weight of talc, 3 to 15% by weight of titanium white, and 0.1 to 5% by weight of a fatty acid metal salt, characterized in that the gelatin-containing layer which is in contact with said support has been incorporated with a combination of a compound having at least two ethyleneimino groups in one molecule with at least one water-dispersible particulate high molecular substance composed of a homopolymer of ethyl acrylate or butyl acrylate, or a copolymer of at least one of ethyl acrylate and butyl acrylate.
 8. A polypropylene support as claimed in claim 3, which bears thereon a light-sensitive silver halide photographic emulsion to form a light-sensitive pHotographic material.
 9. A polypropylene support as claimed in claim 4 which bears thereon a light-sensitive silver halide photographic emulsion to form a light-sensitive photographic material. 